TinyRadius is a small, fast and reliable Java Radius library capable of
sending and receiving Radius packets as specified by RFC 2865/2866. TinyRadius is not a fully-fledged Radius server, but helps you to implement Radius services in your application.

SerialPortNet is an open source serial port communication library for Microsoft .NET. It's written in c#, implements complete .NET 2.0 specifications, and is designed to allow for multiple OSes and add-on 3rd party Serial to Network adapters.

OpenTCP is a highly robust and portable implementation of the TCP/IP
and Internet application-layer protocols intended for those who
want to implement TCP/IP functionality in truly resource constrained
environments (8/16-bit MCUs).

An open source bluetooth stack for Linux (and other operating systems). Support for SDP/L2CAP/RFCOMM.
No further development is expected for this project as BlueZ has taken the official role as bluetooth stack for Linux.

Antitheft software for WM5 and WM6 phones with GPS module(tested on Eten X500+ and Mio A701). Useful for searching of lost/stolen phones and children monitoring. Can monitor sim card changes. Coordinates of the phone can be acquired by SMS.